Roll stabilization system



July 4, 1961 GEORGE 2,991,470

ROLL STABILIZATION SYSTEM Filed Feb. 3, 1953 3 Sheets-Sheet 1 PHASE SHIFTER MODULATOR LOCAL OSCILLATOR WAVEGUIDE DETECTOR (CRYSTAL MlXER) INVENTOR. l/EMQ}! A]. 650x 5 i BY T0 wms y 1961 H. H. GEORGE 2,991,470

ROLL STABILIZATION SYSTEM Filed. Feb. 5, 1953 3 Sheets-Sheet 2 GLOGKWISE ROLL 5mm COUNTER OLOOKIISE ROLL ERROR DISK NEUTRAL DISK NEUTRAL A0 5 A s i l I I i i l FIG. 5.

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RQLL STABILIZATION SYSTEM.

Filed Feb. 3. 1953 3 Sheets-Sheet 5 INVENTOR. HENRY #6150266 ATTORNEYS ice 2,991,470 7, ROLL STABILIZATION SYSTEM Henry H. George, Silver Spring; Md, as'signor to the" represented by the Sec-- United States of America as retary of the Navy Filed Feb. 3, 1953,5Sen

8 Claims. c1.s43 1 This invention pertains generally tojroll stabilization, systems for aerial missiles, and more'particularly to a.

roll polarimeter for an aerial missile which utilizes phase modulation of the cross polarization component of a received vertical polarized microwave signal.

One of the objects of this invention is to provide a roll stabilization system for an aerial missile" which will utilize a phase shifter modulator therein.

Another object of this invention is to provide a roll polarimeter for the intelligence portion of the roll stabilization system of an aerial 1nissi l e'. v, p 'ji To provide an improved r'oll stabilization system for an aerial missile which. is simple and reliable in operation, compact, and economical to construct, are objects of this invention.

Other objects and many o'fithe attendant advantages of. this invention will be readily, appreciated as the same becomes better understood by reference toithe following detailed description when considered "injconnection withthe accompanying drawings, aiid in'which:

FIG. 1 is a block diagram of the roll intelligence system, embodying therein a roll polarimeter;

FIG. 2 illustrates vector diagramsfor the clockwise roll and for the counter-clockwise roll error signals;

FIG. 3 also illustrates ,vectordiagrams for the resulting modulation of the sumsignals for clockwise and counter-clockwise roll signal errors; and

FIG. 4 is a graph showing the phase comparator outa mechanical phase shifter. q

In accordance with theinven'tion, a roll stabilization system is provided for an aerial missile.;; This system makes use of a roll polarin'ieter' for the intelligence portion of the system whichutilizes phasemodulation'of the cross polarization component ofa received vertical polarized microwave signal. The polarimeter includes put as a functionof roll angle for the polarime'ter using an antenna means which terminates'in twdrectangular waveguides, such that the arms of the two waveguides are positioned to receive the vertical and horizontal components of the antenna signal, respectively, together with,

means for summing together the signal outputs from the two arms of the waveguides,rneans for detectingthe sum signals, and means in the arm of one of the waveguides including a disk to phase modulate the signal therein, and means in the arm oftheother waveguide to shift the phase of the signal therein so that the'signals in'the arms of the two waveguides are, 9 Q,..apart from the neutral position of .the disk, Additional means, are provided for amplifying, detecting and filtering the signal from the detecting means. This signal is then fed to a roll servo system, which, in turn, controls the positions of the Wings of the aerial missile.

Referring now to FIG. 1 of the drawings, there is shown a non-polarizing antenna 10 which is mounted on one of the fins 11 of an aerial missile, which fin is normally located 45 to the vertical, and which terminates in two rectangular waveguides 12 and 14. The arm of waveguide 14 is positioned to receive the vertical component of the antenna signal, while the arm of waveguide 12 is positioned to receive the horizontal component of the antenna signal.

The outputs of the two arms are summed together in a magic T 16, and the signal therefrom is fed to a waveguide detector 18 (crystal mixer). It is to be emwould be a zero radio frequency signal in the arm of phasized at this point that the signal may be superheterodyned or videoed as required.

The signal in the arm of waveguide 12 is phase modulated by the rotation of the eccentrically mounted dielectric disk 20 in phase shifter modulator 26 which is driven by a motor 22. The motor 22 also drives a reference alternating current generator 24 whose sinusoidal output is equal in frequency to the revolutions per second of the disk 20 as well as being mechanically phase locked to it.

A phase shifter 29 (or line stretcher) in the arm of waveguide 14 is adjusted so that the signals in the arms of waveguides 12 and 14 are 90 apart for the neutral position of the disk 20. For maximum insertion of the disk 20 in the-arm of the waveguide 12, the signal from this arm is delayed an additional Hence, the signals are 135 apart. For minimum insertion of the disk 20 in the arm of waveguide 12, the signal from the arm' of'waveguide 12 is effectively advanced 45 from the neutral position-so that the signals for this condition are approximately 45 apart. It is to be noted that the horizontal component for a clockwise roll position error is180 from a counter-clockwise roll position as illustrated in FIG. 2.

The vector diagrams of the outputs from the arms of diagrams. There would be no horizontal vector fora zero roll angle, that is, all the radio frequency signal would enter the arm of waveguide 14. Hence, there waveguide 12 to be phase modulated so that the zero roll means zero modulation. The latter is not shown in the vector diagrams of FIG. 3.

Referring again to FIG. 1 of the drawings, the output I of the detector arrangement 18 is amplified by a conventional intermediate frequency amplifier 28 and the amplitude modulationsignal is detected by a conventional staircase detector 30. The output of the detector 30 maybe a complex wave form made up of several audio frequency signals. These audio frequency signals are separated by of information is separated from the other audio signals by audio band pass filter 35. The purpose of filter 35 is to eliminate modulation frequencies other than.

the 75 cycle modulation frequency of [the phase shift modulator 26. The filtered signal from filter 35 is then fed to the roll phase comparator 32.

This 75 cycle signal and the sinusoidal signal output U of the reference generator 24 are phase sensitive rectified by the roll phase comparator 32 to produce a D.-C.' output voltage, which is fed to the roll servo system 34 as indicated. In FIG. 4 there is illustrated of a plot of the D.-C. voltage output of the roll phase comparator 32 vs. roll angle of the missile for an experimental model.

A phasing network (R-C network) (not shown) is required in the sinusoidal voltage leads 36 to the phase comparator 32 to phase the voltage for maximum efficiency of the phase comparator 32 shown in FIG. 1. It is to be noted that zero voltage occurs at and at 270, as shown in FIG. 4. The slope of the curve of D.-C. volts vs. degrees of roll angle is opposite to the slope through 0 roll angle. An ambiguity an'ses at 180 which necessitates a method of sensing by use of a supplemental or additional poor roll device in the servo system. This can be achieved by utilizing a small and inexpensive gyro- Patented July 4., 1961.

scope. It isbelieved that the arrangement described so far provides accurate information in the range of :45 on either side of zero roll position. This polarimeter system requires no additional tubes whenused with a receiver (not shown) that already has, an intermediate 5 frequency amplifier and a staircase detector;

The signal from the roll phase comparator 3-2, asiindicatedabove, is fedto a roll servo system, which, in turn, controls, a mechanical linkage. The mechanical'linkagef is attached to the wings of the aerial missile and is used' to position the wings in order to roll stabilize the missile.

Inaddition, two or more channels of intelligence may be abstracted from the amplitude modulation of the pulses by the filters 31 and. 33. One of. these in the system constructedis a 400 cycle signal used in the automatic frequency control of the local oscillator, which is'part of the waveguide detector 18, and'theother channel was a cycle error frequency signal utilized'in the missile guidance control system.

Obviously many modifications and variations of the 0 present invention are possible in the light of the above. teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1; In a roll stabilization system for an aerial missile,- a rollpolarimeter for the intelligence portion of said'sys: tem which utilizes phase modulation of the cross polarizationcomponent of a received vertical polarized microwave signal, comprising, an antenna means which termi- 30 natesin two rectangular waveguides, the arms of 'the first. and second waveguides being positioned to receive the vertical and horizontal components, respectively, of the. antenna signal, means for summing together the signal outputs from said first and second arms of said. 'wave guides, means for detecting said summed signal, means in the arm of said second waveguide including a disk to phase modulate the signal therein, means in the arm of said first waveguide to shift the signal therein so that the signals in the arms of said first and second waveguides 40 are 90 apart from the neutral position of said disk, and, additional means for amplifying, detecting and filtering the signal from said detecting means.

2. In a roll stabilization system for an aerial missile, aroll polarimeter forthe intelligence portion of said, system which utilizes phase modulation of the cross polarizationcomponent ofa received vertical polarized micro,- wave signal, comprising, anrantenna means whichtermi nates in two rectangular waveguides, the arms of 'thefii'st, and second. waveguides beingpositioned to receive. the vertical; and horizontal components, respectively, .o'f' 'the antenna. signal, means for summing together the signal outputs from, said first and second arms of'said' waveguides, means for detecting said summedsignal,' meansv inthearm of said second waveguide including a disk. to phase modulate the signal therein, a reference alterhating cur-rent generator whose sinusoidaloutput is equal. in frequency to the revolutions per second of saiddisk as well as being mechanically locked to it, means in the arm. of said first wavegiude to shift the signal therein,

so that the signals in the arms of said first and second waveguidesare apart" from the neutral position of said disk, additional means for amplifying, detecting and filtering the signal from said detecting means, and means for phase sensitive rectifying the sinusoidal signal from said detector. and-thesinusoidalF signal from said reference generatonto produceadirectcurrent voltage which is. fdttO the roll-(system.

3. In a roll stabilization system forr'an aerial missile, a roll polarinieterfor the intelligenceportion' of'said system which utilizes phase-modulation of thecross polarization component of..a received vertical polarized microwave signahflcomprising, a non-polarizing antenna which terminates intwo rectangular waveguides, the arms of the first, and second" waveguidesbeing positioned to receive the verticaland horizontalicomponents, respectively, of the antenna signalgrneansforsumming. together. the signal outputsfr'omsaidfii st andfsecond' arms of said waveguides, means for detecting said summed signal, means inthe arm of,v saidseco'ndwaveguide including a disk to phase modulate the, signal therein, areference alternating current generator whose. sinusoidal output is equal 7 in frequency to, the. revolutions per second of said disk asjwell, asbeingzmechanicallylocked to-it, means in the arm ofsaid'first waveguide to shiftthe. signal therein so that the signals in the arms of said'first and second waveguidesiaresuhstantially, 903 apartfromuthe neutral position of,saidzdisk,'additionalmeans for amplifying, detecting.;andfiltering, thelsignalifr'om said .detecting means, and. means, for; phase sensitive. rectifying. the. sinusoidal signal from said.detec tor. and thersinusoidal signal from said.referencengenerator.tolproduce adirect current voltage which is fedtto.thetrolh-systemof said. aerial missile.

4. Anyarrangernentasseoforth in claim 3, wherein said means:fortsunnning ,tog ether. the signal outputs from the armsof said-waveguideszcornprises arnagic T.

5.- An arrangementi asset forth in:claim 4, wherein the means in the armaof said-.second waveguide comprises aneccentrically; mountedidielectricdisk in a phase shifter modulator.

6. An arrangement as set forth-in claim 5, wherein the detectingtmeanscomprises. a, waveguide detector of the crystal mixer type.-

7. A-nrarrangement asssetaforthin claim 6, wherein the shifting, rneans in'thevarmtof said first waveguide for said signal ,therein comprises :a phase shifter.

8. Anarrangement as-set forthin claim-7, wherein the meansgfor-phase sensitive rectifying, said output signals frornsaid; amplifying, detecting and, filtering means and fromsaid:reference-generator comprises -a roll phase comparator:

References (iitedinrthefile of this'patent UNITED; STATES PATENTS.

2,272,869 Hammond: Feb. 10, 1942 2,362,832 Landi Nov. 14, 1944 2,616,640 Bedford Nov. 4, 1952 2,61956-3'5 Chair-.. Nov. 25, 1952 

